I am not going to sugar coat this. Unless you know how to work with WordPress code (PHP, HTML, JS and CSS) and more specifically, WordPress child Themes, you shouldn't be making changes to your purchased Theme except through the WordPress Admin panel.
https://developer.wordpress.org/themes/advanced-topics/child-themes/
A WordPress installation consists of about 800 folders and 1,500 files but not one of those files is a complete web page. They are all bits and pieces of code that get assembled by the server and populated with content from the MySQL database. So while you can certainly edit your Theme's code in Dreamweaver, you're not going to get a WYSIWYG experience. And once the site is deployed on your server, you MUST maintain it via your online Admin panel. You cannot use Dreamweaver to edit the site because as I said above, there are no actual web pages to edit. WordPress is all dynamically driven.